UT.6.01

Alapok

2.2 Beágyazott rendszerek

Processzor típusok: x86 (ált. asztali gép), ARM.
"Az I/O az a ragasztó, amivel a processzor kapcsolódik a világhoz."
Tervezési szempontok: tesztelhetőség, haszon, energia igény, méret, megfelelő válasz megfelelő időben.
Human-computer interface (HCI) or man-machine interface (MMI).
Tipikus példa: multiméter.

2.3 Bevezetés a számítógépekhez

Számítógép = proceszor + RAM + ROM + IO.
Neumann architecture, Harvard "A port is a physical connection between the computer and its outside world. Ports allow information to enter and exit the system."
"A bus is a collection of wires used to pass information between modules."
"Static RAM (SRAM): using six metal-oxide-semiconductor field-effect transistors (MOS or MOSFET) to create each memory bit. Four transistors are used to create two cross-coupled inverters that store the binary information, and the other two are used to read and write the bit." RAM random access memory

ROM-ok: ROM (read only memory)

Static RAM (SRAM)

Programmable ROM (PROM) 10000 times slower RAM

Electrically erasable programmable PROM (EEPROM)

In regular EEPROM, you can erase and program individual bytes. "Flash ROM is a popular type of EEPROM. Each flash bit requires only two MOSFET transistors. The input (gate) of one transistor is electrically isolated, so if we trap charge on this input, it will remain there for years."

FLASH ROM

Each flash bit requires only two MOSFET transistors The input (gate) of one transistor is electrically isolated, so if we trap charge on this input, it will remain there for years. The other transistor is used to read the bit by sensing whether or not the other transistor has trapped charge.

Flash ROM must be erased in large blocks. On many of Stellaris family of microcontrollers, we can erase the entire ROM or just a 1024-byte block.

Because flash is smaller than regular EEPROM, most microcontrollers have a large flash into which we store the software. For all the systems in this class, we will store instructions and constants in flash ROM and place variables and temporary data in static RAM.